Temperature compensating flux ring

(19)

(11)

EP 1 255 058 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	17.12.2003 Bulletin 2003/51

(43)	Date of publication A2:
	06.11.2002 Bulletin 2002/45

(21)	Application number: 02076562.4

(22)	Date of filing: 22.04.2002

(51)	International Patent Classification (IPC)⁷: F16F 9/53, F16F 9/52

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
	Designated Extension States:
	AL LT LV MK RO SI

(30)

Priority:

30.04.2001 US 845707

(71)	Applicant: Delphi Technologies, Inc.
	Troy, MI 48007 (US)

(72)	Inventors:
	Robinson, Frank M. Oakwood, OH 45419 (FR) Kime, Aaron A. Cincinnati, OH 45246 (FR)

(74)	Representative: Denton, Michael John
	Delphi European Headquarters, 64 avenue de la Plaine de France, Paris Nord II, BP 60059, Tremblay-en-France 95972 Roissy Charles de Gaulle Cédex 95972 Roissy Charles de Gaulle Cédex (FR)

(54)	Temperature compensating flux ring

(57) A piston assembly (16) for magneto rheological (MR) fluid vibration damper affixed to a suspension system includes a piston that strokes inside a housing (12) to dampen vibrations. The piston includes a core (18) affixed to a piston shaft (20). An electric coil (22) is affixed to the core and is coaxially aligned with the piston shaft. A sleeve (26) circumscribes the piston core having a wall (27) with a first inner diameter. An annular fluid passage (28) is formed between the sleeve and the core. Fluid passes through the annular passage when the piston strokes inside the damper. The wall includes a channel (32) having a second inner diameter greater than the first inner diameter. The channel reduces resistance to the piston from the MR fluid derived from temperature induced viscosity variations.

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